Vehicle axle apparatus

ABSTRACT

A vehicle axle construction comprises a suspension for supporting the axle from first and second frame rail members. Elongated support members extend forwardly from respective locations along the frame rail members that are rearwardly of the axle and are clamped or otherwise coupled to the axle. A single pivot may be utilized to couple the respective rearmost end portions of the supports to the respective frame members. The forward ends of the supports may be coupled to respective air springs. Desirably, at least a portion of each air spring is positioned forwardly of the axle. In addition, at least one lateral stabilizer rigidifies the suspension. An alternative suspension utilizes leaf springs. A double acting rack-and-pinion steering mechanism may be rigidly coupled to the axle for use in steering the wheels of the vehicle.

RELATED APPLICATION DATA

This application is a divisional application of U.S. patent applicationSer. No. 10/956,770; which claims the benefit of U.S. provisional patentapplication No. 60/542,485, filed Feb. 6, 2004, entitled, “Vehicle AxleApparatus”, by Michael von Mayenburg, Sean Tabari, James V. McHorse,David A. Sukowatey, Andrew H. Wedam and Matthew G. Markstaller, and U.S.provisional patent application No. 60/566,978, filed Apr. 29, 2004,entitled, “Vehicle Axle Apparatus”, by Michael von Mayenburg, SeanTabari, James V. McHorse, David A. Sukowatey, Andrew H. Wedam andMatthew G. Markstaller, which are hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to vehicle axle apparatus and hasparticular applicability to the front steerable axle of a vehicle suchas a truck.

BACKGROUND

Various axle suspension mechanisms are known for suspending a vehicleaxle from frame rails of a vehicle, such as a truck.

In one known form, the axle of a truck is clamped to an elongatedsupport. The support is pivoted to a frame rail at a location forwardlyof the axle and coupled by a double pivot mechanism to the frame rail ata location rearwardly of the axle. An air spring extends between theframe rail and elongated support, at a location rearwardly of the axle.A structure of this type is illustrated in U.S. Pat. No. 6,086,077 toStuart. Other suspension mechanisms are also known. Although thesesuspensions exist, a need nevertheless arises for an improved suspensionsuch as for the front axle of a vehicle to which steerable wheels aremounted.

The axle may be a solid axle with wheels rotatably coupled to therespective end portions of the axle for rotating as the vehicle moves.Solid axles have a central portion extending between frame rails of avehicle and end portions which typically project outwardly beyond theframe rails. A respective wheel support is pivoted to each end of theaxle for pivotal movement about an upright axis to steer the wheelsmounted to the respective wheel supports. The wheels are rotatablymounted to the wheel supports for rotation as the vehicle is driven. Ina simplified form, solid axles are of a one-piece monolithic unitaryconstruction. By monolithic, it is meant that they are not made of aplurality of parts which are assembled into the construction. Althoughmechanisms are known for steering the wheels mounted to a solid axle, aneed exists for improved steering mechanisms for this purpose.

The present invention relates to new and unobvious improvements invehicle axle mechanisms as set forth in the claims below. The presentinvention is not limited to vehicle axle constructions which combine allof the features disclosed herein, but instead are directed toward noveland unobvious aspects of the invention both alone and in variouscombinations and subcombinations with one another.

SUMMARY

In this disclosure, the term “coupled” includes both direct connectionand indirect connection through one or more other components. Inaddition, the term “a”, with reference to a particular component,encompasses one or more of the components because the inclusion, forexample, of two of the components means that “a” component is present.In addition, the term “including” has the same broad meaning as the term“comprising”.

In accordance with one embodiment, a vehicle comprises a solid axle andfirst and second spaced apart elongated frame rail members from whichthe axle is suspended. A solid axle desirably provides torsionalstiffness to a suspension. The frame rail members each comprise a frontor forward end portion nearest to the front of the vehicle and a rear orrearward end portion nearest to the rear of the vehicle. The axlecomprises first and second opposed axle end portions. At least one wheelis rotatably mounted to each axle end portion with the wheels beingrotatable about a wheel axis.

In one embodiment, a suspension for a solid axle of the vehiclecomprises first and second elongated suspension supports, first andsecond air springs, at least one cross-member and at least one elongatedlateral stabilizer member. In this embodiment, the first supportcomprises a first end portion pivotally coupled to the first frame railmember at a first location rearwardly of the axle. The first supportalso comprises a second portion coupled to the axle. The second supportsimilarly has a first end portion pivotally coupled to the second framerail member at a second location rearwardly of the axle and a secondportion coupled to the axle. The first air spring is coupled to thefirst frame rail member and to the first support. Desirably, in thisembodiment, at least a portion of the first air spring is positionedforwardly of the axle and wheel axis. In one specific form, the firstair spring has a first upright air spring axis which is positionedforwardly of the wheel axis. The second air spring in this embodiment isalso desirably coupled to the second frame rail member and to the secondsupport. The second air spring also desirably has at least a portionpositioned forwardly of both the axle and of wheel axis. In one specificembodiment, the second air spring has an upright air spring axis whichis positioned at a location forwardly of the wheel axis and axle. Thecross-member of this embodiment desirably has a first end portioncoupled to the first frame rail member adjacent to the first air springand a second end portion coupled to the second frame rail memberadjacent to the second air spring. In a desirable in this embodiment,the lateral stabilizer member has a first end portion positioned nearerto and pivotally coupled to one of the first and second frame railmembers and a second end portion pivotally coupled to the axle at alocation adjacent to the other of the first and second frame railmembers.

The suspension in accordance with an embodiment also comprises a firstshock absorber that may be positioned forwardly of the first air spring.The first shock absorber desirably comprises a first end portionpivotally coupled to the first frame rail member and a second endportion pivotally coupled to the axle. This embodiment also comprises asecond shock absorber which may be positioned forwardly of the secondair spring. The second shock absorber in this embodiment desirablycomprises a first end portion pivotally coupled to the second frame railmember and a second end portion pivotally coupled to the axle.

In accordance with an embodiment, at least one cross-member and at leastone lateral stabilizer member such as a track member, for example atrack rod or track bar, may be positioned at respective locations alongthe length of the first and second frame rail members with therespective locations desirably being positioned forwardly of thelocations where the respective elongated supports are coupled to theframe rail members and rearwardly of any shock absorbers included in thesuspension.

In a desirable form, the solid axle includes first and second axle endportions. The vehicle also comprises first and second wheels rotatablycoupled to the respective first and second axle end portions, as byfirst and second wheel supports pivotally carried by the respective axleend portions. The wheels rotate about a wheel axis as the vehicle moves.The first and second wheels are also pivotally coupled to the respectivefirst and second axle end portions, such as by the respective wheelsupports, for pivoting about respective first and second uprightsteering axes and relative to the axle to steer the vehicle. Thisembodiment desirably comprises a rack-and-pinion wheel steerer coupledto and supported by the axle. The steerer comprises first and secondrack-and-pinion end portions respectively coupled, desirably via firstand second wheel supports, to the respective first and second wheels.The rack-and-pinion steerer is operable to selectively shift the firstand second rack-and-pinion end portions in a first direction to pivotthe wheels about the respective first and second steering axes in onedirection. The rack-and-pinion steerer is also operable to selectivelyshift the first and second rack-and-pinion end portions in a directionopposite to the first direction to pivot the wheels about the respectivefirst and second steering axes in a second direction opposite to saidone direction.

In a desirable embodiment, the rack-and-pinion wheel steerer ispositioned rearwardly of the solid axle. Desirably, the axle shields allbut the end most portions of the rack-and-pinion steerer from the front.In accordance with an embodiment, at least one cross-member and at leastone lateral stabilizer member may each be positioned at a location alongthe length of the respective first and second frame rails at a locationwhich is both rearwardly of the axle and forwardly of therack-and-pinion steerer. In a specific form, the at least onecross-member and at least one lateral stabilizer member may each have acentral portion positioned between the axle and rack-and-pinion steererduring at least certain operating positions of the suspension.Desirably, the central portions of the at least one cross-member and ofthe at least one lateral stabilizer are positioned at an elevation whichis below the elevation of the frame rail members.

In accordance with an embodiment, first and second axle couplers areprovided. The first and second axle couplers are respectively positionedbelow, but not necessarily overlaid by, the first and second frame railmembers. Each such axle coupler desirably comprises a rearwardlyprojecting rack-and-pinion supporting portion to which the one endportion of the rack-and-pinion steerer is coupled. Each axle coupleralso desirably comprise a forwardly projecting shock absorber supportingportion to which an end portion of a shock absorber is coupled tothereby couple the shock absorber to the associated frame rail member.

In an embodiment, at least one of the first and second axle couplers maycomprise a stabilizer coupling portion to which a first end portion ofat least one lateral stabilizer member is pivotally coupled so as tothereby pivotally couple the first stabilizer end portion to the axle.The axle coupler may be mounted at least in part to an upper surface ofthe axle. Also, the stabilizer coupler portion may comprise an upwardlyprojecting stabilizer mounting portion. The stabilizer end portion thatis opposite to the first stabilizer end portion may be pivoted to the atleast one cross-member such as at a location adjacent to a frame railmember. As a desirable feature, a cross-member reinforcement may berigidly coupled to the frame rail member and also to the at least onecross-member at the location where the at least one lateral stabilizermember is pivoted to the at least one cross-member.

In one embodiment, first and second rail coupling brackets may berigidly supported by the respective first and second frame rail members.The coupling brackets may each comprise an air spring retaining portioncoupled to an upper portion of an associated air spring and across-member engaging portion. The end portions of the at least onecross-member may be coupled to, and desirably are directly mounted to,the respective cross-member engaging portions and are thereby coupled tothe associated frame rail members. The cross-member engaging portionsare desirably located rearwardly of air springs and forwardly of theaxle.

Support coupling assemblies are each mounted to a respective associatedone of the frame rail members. Each support coupling assembly pivotallycouples the rear end portion of a respective one of the elongatedsuspension supports to the associated frame rail member. Desirably, thesupport coupling assemblies each define a single pivot axis as the onlypivot axis about which the end portion of the associated elongatedsupport pivots relative to the associated frame rail member.

In one form, each of the first and second frame rail members may begenerally of a C-shaped cross-section having upper and lower flangeportions and an upright web portion extending between the flangeportions. Each of the support coupling assemblies, in one specific form,comprises one bracket portion that comprises an upwardly projectingflange portion mounted at least in part to the web portion of theassociated frame rail member and another bracket portion that comprisesa frame rail mounting portion configured for mounting at least in partto the undersurface of the lower flange portion of the associated framerail member. The pivot axis for the end portion of the associatedelongated suspension support is desirably defined between the bracketportions at a location below the lower flange portion of the associatedframe rail member.

In one embodiment, at least one elongated lateral stabilizer membercomprises a first end portion pivotally coupled to a cross-member at afirst location and a second portion pivotally coupled to one of thefirst and second suspension supports. At least one of the first andsecond elongated suspension supports may comprise an extension portionwhich projects forwardly of the axle. In this latter embodiment, thesecond end portion of the at least one lateral stabilizer is desirablypivotally coupled to, and may be directly pivotally connected to, theextension portion and the first location is at a position of the atleast one cross-member that is spaced from end portions of thecross-member.

In desirable embodiments, the suspension comprises only one lateralstabilizer at the location of the suspension. Alternatively, and lessdesirably, plural lateral stabilizer members may be included in thesuspension although this adds weight to the suspension. The elongatedsuspension supports may be of a plural piece construction. However, inone desirable form, the first and second elongated suspension supportsare each of a unitary one-piece monolithic construction such as beingcast, stamped, formed or machined out of starting material, with steelbeing a specific example.

In a further embodiment, the suspension comprises a solid axle with arack-and-pinion steerer positioned rearwardly of the axle and with theaxle coupled to each frame rail by a leaf spring based suspension. Theleaf spring may be pivotally coupled to the associated frame rail forpivoting about a single pivot axis at the front of the leaf spring andcoupled by linkage to the frame rail at the rear of the leaf spring withthe linkage accommodating a double pivot.

Again, the invention is directed toward novel and unobvious aspects ofvehicle axle mechanisms described herein both alone and in varioussubcombinations and combinations with one another, as set forth in theclaims. The invention also encompasses novel and unobvious methodscomprising combinations and subcombinations of method acts as disclosedherein.

DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 are perspective views of a vehicle front axle suspendedfrom first and second frame rail members in accordance with oneembodiment.

FIG. 3 is a side elevational view of the embodiment of FIG. 1.

FIG. 4 is a top view of the embodiment of FIG. 1.

FIG. 5 is a front elevational view of a portion of the assembly of FIG.1.

FIG. 6 is a rear elevation view of a portion of the assembly of FIG. 1.

FIG. 7 is a partially exploded view of selected components of anembodiment of a suspension.

FIG. 8 is a partially exploded view of additional components of asuspension together with the assembled components of FIG. 7.

FIGS. 9 and 10 are partially exploded views of the suspension of FIGS. 7and 8 with additional components depicted therein.

FIG. 11 is a perspective view of one form of axle coupler.

FIG. 12 is a top view of the coupler of FIG. 11.

FIG. 13 is a side elevational view of the coupler of FIG. 11.

FIG. 14 is a perspective view of another form of axle coupler.

FIG. 15 is a top view of the axle coupler of FIG. 14.

FIG. 16 is a side elevational view of the axle coupler of FIG. 14.

FIG. 17 is a perspective view of an embodiment of an axle with arack-and-pinion steering mechanism similar to the rack-and-pinionsteering mechanism of FIG. 1 (but with a suspension omitted forclarity).

FIG. 18 is a perspective view of another form of axle andrack-and-pinion steering mechanism usable with a suspension system suchas shown in FIGS. 1 and 2.

FIG. 19 is a bottom view of the embodiment of FIG. 18.

FIG. 20 is a perspective view of a vehicle front axle suspended fromfirst and second frame rail members in accordance with anotherembodiment.

FIG. 21 is a side elevational view of the embodiment of FIG. 1,including a shock absorber.

FIG. 22 is a bottom view of the embodiment of FIG. 1.

FIG. 23 is a top view of the embodiment of FIG. 20.

FIG. 24 is a perspective view of a further embodiment of a suspensionwith a rack-and-pinion steerer.

FIG. 25 is a top view of the embodiment of FIG. 24.

FIG. 26 is an exploded view of components included in the embodiment ofFIG. 24.

FIGS. 27 and 28 are enlarged views of respective mounts which may beused to couple the rack-and-pinion steerer to the axle in the embodimentof FIG. 26.

FIG. 29 is a side elevational view of the embodiment of FIG. 24.

FIG. 30 is a front view of the embodiment of FIG. 24.

FIG. 31 is a rear view of the embodiment of FIG. 24.

DETAILED DESCRIPTION

With reference to FIGS. 1-6, a vehicle embodiment 10 is illustratedwhich comprises first and second frame rail members 12,14. Theillustrated frame rail members 12,14 comprise sections of spaced apartelongated frame rails of a vehicle such as a truck. Members 12 and 14may be bolted or otherwise secured to other frame rail components whichtogether form elongated frame rails of a vehicle having a longitudinalaxis which extends in a fore and aft direction. Members 12,14 may alsocomprise complete frame rails rather than frame rail sections, ifdesired. The sections 12,14 have respective front or forward ends 16,18and rear or rearward ends 20,22. The word “forward” refers to adirection toward the front of the completed vehicle while the word“rearward” refers to a direction toward the rear of the vehicle. Aradiator (not shown in FIG. 1) or radiator supporting brackets (also notshown in FIG. 1) may be mounted to the front ends 16,18 of therespective rail members 12,14.

An axle 30 is positioned below the frame rail members 12,14 and extendstransversely relative to the frame rail members. That is, axle 30extends across the space between frame rail members 12,14 and desirablyextends outwardly beyond the frame rail members. For example, in theembodiment of FIGS. 1-6, axle 30 has opposed end portions 32,34 whichextend outwardly beyond the outer surfaces of the respective frame railmembers 12,14. Most desirably, the axle 30 is perpendicular to the framerail members. The illustrated axle 30 in this embodiment is a solid axlewhich spans the distance at least between frame rail members 12,14. Thesolid axle functions as a torsional stabilizer bar. By solid axle it ismeant that the axle is not articulated. Thus, the respective wheels38,40, and tires 42,44 supported by the respective wheels 38,40, at therespective end portions 32,34 of the axle are not supported byindependently upwardly and downwardly movable axle components.

A first wheel support 46 comprises a wheel supporting axle extension 50to which wheel 38 is rotatably mounted for rotation about a wheel axis54. The tire 42 is carried by wheel 38 and thus the wheel 38 andsupported tire 42 rotate about axle extension 50 and the wheel axis 54as the vehicle moves. A second wheel support 48 is coupled to axle endportion 34. Wheel support 48 comprises a wheel supporting axle extension52 to which the wheel 40 is rotatably mounted. The wheel 40, and tire 44carried by the wheel 40, rotate about axle extension 52 and morespecifically about a wheel axis 56 as the vehicle moves. With solid axle30, the axes 54 and 56 are aligned with one another during normaloperation of the vehicle.

In the illustrated embodiment of FIGS. 1-6, the axle 30 comprises thefront axle of a vehicle and the wheels 38,40 are steerable to steer thevehicle. It should be noted that the suspension described herein is notlimited to an application to the front axle of a vehicle, although thisis a most desirable application. In the embodiment shown in thesefigures, the wheel support 46 is pivotally coupled to axle end portion32 by a pivot 60 for pivoting about an upright pivot or steering axis 62(shown in FIGS. 1 and 5). Also, the wheel support 48 is pivotallycoupled by a pivot 64 (FIGS. 1 and 5) for pivoting about an uprightpivot or steering axis 66.

Although various steering mechanisms may be used to pivot the wheelsupports 46,48 about the steering axes 62,66, desirably arack-and-pinion steering assembly comprising a rack-and-pinion steerer70, such as described in greater detail below, is provided for thispurpose.

The illustrated vehicle 10 desirably comprises at least one transverselyextending cross-member 80 which interconnects the frame members 12,14.Additional cross-members may be provided. In the embodiment of FIG. 1,only one such cross-member is desirably used and is positioned near theaxle 30. The cross-member 80 may be generally U-shaped (see for exampleFIG. 9) to provide clearance for an engine or other components of thevehicle. Respective end portions 82,84 of the illustrated cross-member80 are coupled to the respective frame rail members 12,14. Morespecifically, as shown in FIGS. 1 and 2, the end portions 82,84 extendupwardly along the outside surfaces of the respective frame rail members12,14 for coupling thereto as explained below. An intermediate orcentral portion 86 (FIG. 1) of the cross-member 80 is positioned belowthe frame rail members and is desirably positioned in the spacerearwardly of axle 30 and forwardly of rack-and-pinion steerer 70.

As previously mentioned, the solid axle 30 is positioned below and isspaced from the frame members 12,14 by the vehicle suspension. Oneembodiment of a suspension, indicated generally at 90 in FIG. 1 forframe member 12, is provided for coupling the axle to the respectiveframe member 12. A similar suspension 100 is desirably used to couplethe axle 30 to the frame member 14.

In the form of suspension 90 illustrated in FIGS. 1-6, a first elongatedsuspension support 110 is provided and extends in a fore/aft direction.The illustrated support 110 desirably has a longitudinal axis which isparallel to the longitudinal axis of frame member 12. The support 110may be of a plural piece construction but, desirably, is of a singlepiece configuration and may be formed by, for example, stamping. In thisexample, in the event of excessive impact, support 110 would tend tobuckle or bend rather than break. In this example, the support 110 is amonolithic one piece component. By monolithic, it is meant that thereare no welds or other assemblies of plural components to form thesupport 110. The illustrated support 110 comprises a body having a firstend portion 112 pivotally coupled to frame rail member 12 at a locationrearwardly of axle 30. In addition, support 110 comprises a secondportion 114, which may comprise an end portion of support 110, which iscoupled to the axle 30. For example, a clamp or more desirably an axlecoupler, one form of which is indicated at 116 in FIG. 1, may be used torigidly clamp or connect the body of elongated support 110 to the axle30 so as to prevent fore/aft sliding of the support 110 relative to theaxle 30.

In the embodiment shown in FIGS. 1-6, the rearmost end portion 112 ofsupport 110 is coupled to the frame rail 12 by a support assembly 120such that support end portion 112 pivots about a pivot axis 122 relativeto the frame rail 12. Pivot axis 122 is desirably parallel to the wheelaxis 54. Most desirably, and although not required, the support 110pivots relative to frame rail member 12 about only a single pivot axis,in this case pivot axis 122. That is, a double pivot connection iseliminated in this illustrated embodiment. The support assembly 120 inthe illustrated embodiment is desirably bolted or otherwise rigidlysecured to frame member 12 and will be described in greater detailbelow. In the illustrated example, the rearward positioning of support110 frees up the front end of the frame rails to accommodate vehiclecomponents such as a larger radiator.

A first air spring 130 is coupled at an upper portion thereof to framerail 12 and at a lower portion thereof to the axle 30. The lower portionof air spring 130 may be coupled to the axle through another component,such as by axle coupler 116. Although the air spring 130 may be coupledto the frame rail 12 in any convenient manner, in one desirableapproach, a rail coupling bracket, such as indicated at 132 in FIG. 2,is rigidly supported by and mounted to the first frame rail member 12.More specifically, the frame rail member 12 may be of a C-shapedcross-section having upper and lower flange portions 134,136 and anupright web portion 138 extending between the flange portions 134,136.The illustrated rail coupling bracket 132 comprises a first air springretaining portion, such as an outwardly projecting flange 140, coupledto an upper portion of air spring 130. The rail coupling bracket 132 mayalso comprise a back portion 142 mounted to the web 138 of frame rail12. Fore-and-aft gusset or reinforcing portions 144,146 may also beincluded in the bracket 132 for interconnecting back 142 and flange 140to reinforce the flange. Other reinforcing gussets may also be providedto strengthen bracket 162. Desirably, the portions 144,146 extendoutwardly from web 138 and perpendicularly to the web. The rail couplingbracket 132 also desirably comprises a cross-member engaging portionwhich, in the illustrated embodiment, comprises the reinforcing flange146. In the illustrated embodiment, the upper end portion 82 ofcross-member 80 is bolted or otherwise rigidly secured to flange 146.Thus, bracket 132 performs a dual function of retaining the upperportion of air spring 130 and providing a connection for cross-member80. In addition, the orientation of flange 146, that is the projectionof flange 146 outwardly from web 138, facilitates the connection of thecross-member to the bracket 132. The cross-member may be flat stock asshown in FIG. 2 with the front surface of end portion 82 of cross-member80 abutting the rear surface of bracket portion 146 for convenientmating of these components together as they are connected.

The axle coupler 116 (described in greater detail below) may be of aplural piece construction but, in the form shown, the illustratedexemplary axle coupler is a single piece monolithic element which may becast or otherwise made. The illustrated axle coupler 116 desirablycomprises a rearwardly projecting portion 150 (FIG. 2). Projectingportion 150 comprises one form of a rack-and-pinion supporting portionto which a first end portion 152 of the rack-and-pinion steerer 70 maybe coupled. In addition, the elongated suspension support 110 may alsobe coupled or mounted to the axle coupler portion 150 to rigidify theassembly at this location. A central portion 154 of axle coupler 116 isdesirably coupled to the axle 30 such as by being bolted or otherwiserigidly secured thereto. The lower portion of air spring 130 may also besupported by the central portion 154 of axle coupler 116. In addition,the axle coupler 116 may comprise a forwardly projecting shock absorbersupporting portion, such as in a form indicated at 156, for purposesexplained below. Clamps and other mechanisms may be used in alternativeapproaches for mounting the air spring in the suspension. The air spring130 is desirably detachably mounted in place. The dashed line 160 shownin FIG. 3 coincides with an upright or center axis of air spring 130. Inthe illustrated embodiment, the center line or axis 130 is positionedforwardly of wheel axis 54. A vertical plane extending through wheelaxis 54 is indicated by dashed line 162 in FIG. 3. Thus, in theembodiment shown in FIG. 3, at least a portion of the air spring 130 ispositioned forwardly of the axle. This position of air spring 130provides space for other components located rearwardly of the airspring. Also, by shifting air springs forwardly, the loading on the airsprings is reduced, which permits the use of smaller air springs. Airspring 130 may be shifted to locations other than that shown in FIG. 3(such as rearwardly over axle 30 or further to the rear). A conventionalleveling valve assembly 164 (FIG. 3) and associated controls operate ina conventional manner to control the inflation of air spring 130 such asto level the frame member 12.

As best seen in FIGS. 2 and 3, a shock absorber 170 is desirablyprovided to dampen the motion of the elongated support 110. Theillustrated shock absorber 170 comprises an upper end portion 172 whichis pivotally coupled to the frame rail 12. For example, a mountingbracket 174 (FIG. 2) rigidly secured to web 138 of frame rail 12 maysupport the upper end 172 of shock absorber 170 for pivoting about atransversely extending pivot axis defined by the axis of a pin 176. Thelower end 180 of shock absorber 170 is pivoted to shock absorbersupporting portion 156 of axle coupler 116 by a pin 182 for pivotingabout an axis which is generally parallel to frame rail 12. Shockabsorber 170 is desirably positioned forwardly of the axle and in effectalong an extension of support 110 due to the coupling of the support 110to axle coupler 116. Enhanced shock absorption is provided by thisarrangement because the shock absorber 170 is spaced a substantialdistance from the pivot axis 122 about which support 110 pivots relativeto frame rail 12. Shock absorber 170 thus effectively dampens outvibrations in the suspension.

The rear end portion 112 of support 110 may be coupled to frame member12 in any suitable manner for pivoting relative to the frame rail.Desirably, coupling is accomplished so as to limit the pivoting of endportion 112 of support 110 about a single pivot axis. Again, a supportmechanism such as support coupling assembly 120 may be used for thispurpose. The illustrated support assembly 120 (see FIG. 2) comprisesfirst and second bracket portions 200,202 which are configured toreceive the end portion 112 of support 110 therebetween. A bolt or pin204, carrying a bushing (not shown), is coupled to end portion 112 anddefines the pivot axis 122. As best seen in FIG. 7, a bushing receivingopening 206 extends through end portion 112 of support 110. Theillustrated bracket 200 comprises an upwardly projecting flange portion208 mounted at least in part to the web portion 138 of the first framerail member 12. The second bracket portion 202 comprises a frame railmounting portion 210 (FIGS. 7 and 8), configured for mounting at leastin part to the undersurface of the lower flange 136 of the first framerail member. The pivot 122 is thus defined between the first and secondbracket portions 200,202 at a location below the lower flange portion136 of frame rail member 12.

The suspension desirably comprises at least one elongated lateralstabilizer member, with one example being indicated at 240 in FIGS. 1, 2and 4-6. While more than one lateral stabilizer may be used, in adesirable construction only one is provided. The illustrated elongatedlateral stabilizer member 240 has a first end portion, such as 242,coupled to one of the first and second frame rail members (in thisexample end portion 242 (FIG. 1) is coupled to frame rail member 12). Inaddition, a second end portion, such as 244 (FIG. 2) is pivotallycoupled to the axle 30 at a location adjacent to the other of the firstand second frame rail members (in this case adjacent to frame railmember 14). In the embodiment of these figures, end portion 242 ofstabilizer member 240 is pivoted to the cross-member 80 at a locationintermediate the end portions 82,84 of the cross-member and morespecifically at a location at the interior of frame rail 12. Inaddition, end portion 244 is pivoted to the axle 30 via the axle coupler116′ (see FIG. 2). More specifically, in the illustrated embodiment, theaxle coupler 116′ comprises a stabilizer coupling portion 246 to whichend 244 is pivoted by a pin 248. Thus, in this example, the end portion244 is indirectly pivoted to the axle through the coupler 116′.Alternatively, the lateral stabilizer 240 may be reversed with end 244being pivoted to a coupler 116 adjacent to frame rail 12 and end 242 ofthe coupler then being pivoted to the cross-member adjacent to framerail 14. The stabilizer portion 246 projects upwardly from coupler 116′in the illustrated embodiment and that is positioned inwardly of framerail 14. As best seen in FIG. 9, stabilizer 240 in the illustrated formhas a central portion which is positioned lower than the end portions242,244 and is positioned below the lower portions of the frame rails12,14 so as not to interfere with an engine or other vehicle componentspositioned between the frame rails at this location. In the illustratedembodiment of FIG. 10, the central portions of cross-member 80 and ofstabilizer 240 are positioned between axle 30 and rack-and-pinionsteerer 70 with the stabilizer 240 being located forwardly of thecross-member 80.

The suspension may also comprise a cross-member reinforcement, such as abracket 250 (FIG. 1) rigidly mounted to the frame rail 12. In the FIG. 1embodiment, bracket 250 is mounted to the lower flange 136 of the framerail 12. Bracket 250 projects inwardly from frame rail 12 and comprisesa reinforcing portion 252 positioned to back up the location at whichstabilizer end portion 242 is pivoted to the cross-member 80. Morespecifically, a pivot pin 256 extends through end 242, the cross-member80 and reinforcing portion 252 to pivotally interconnect thesecomponents at this location.

The respective end portions 242,244 of stabilizer 240 are desirablypivoted about axes which are parallel to the longitudinal axes of therespective frame rails 12,14.

As previously mentioned, a suspension, in this case suspension 100, isalso used at the opposite side of the vehicle to couple the axle 30 tothe frame member 14. This latter suspension may be identical to thesuspension 90 (see FIGS. 1 and 2) and for this reason is not describedin detail. In FIGS. 1-6, suspension components corresponding to thosewhich have previously been discussed are indicated by the same numbertogether with a prime (′) designation. Not all of the components ofsuspension 100 have been numbered. Although the support 110′ may extendforwardly to the same extent as the support 110, these components neednot necessarily be of the same length. For example, as explained inconnection with another embodiment described below, one of thesesupports may be extended a greater amount than the other to provide aforward end portion to which a lateral stabilizer may be pivoted.

FIGS. 7-10 depict the embodiment of FIGS. 1-6 in various stages ofassembly. It should be understood that the components need not beassembled in the order shown in these figures. These figures areintended to assist in illustrating a specific embodiment of thesuspension with the invention not being limited to this depictedembodiment.

FIGS. 11-13 depict various views of one embodiment of a coupler 116′with portions thereof discussed above. FIGS. 14-16 illustrate a form ofcoupler 116. One of the differences between these two forms of couplersis that coupler 116 in the illustrated form lacks a stabilizer couplerportion 246.

Desirably, the couplers 116,116′ are precisely located on axle 30 withtight tolerances so that, when the rack-and-pinion steerer is mounted tothe couplers, a tight tolerance is also provided between therack-and-pinion steerer and axle. In one specific alignment approach, acentering hole 155 (FIG. 7) is provided through axle 30. Hole 155 may bein the form of a recess extending partially through the axle. The hole155 may be centered in the bolt receiving pattern through the axle andcan be off-center if desired. In addition, a locating hole 157, whichmay also be in the form of a recess, is provided such as in line andcentered between the two forward clamping bolt receiving holes throughthe axle. Holes 155,157 may be at other locations as they define twolocating references for locating the coupler 116. The underside ofcoupler 116 may include a flat or planar axle engaging undersurface 163(FIG. 16) for positioning on top of a corresponding flat or planar axlemounting surface 165 (FIG. 7) at or adjacent to axle end portion 32. Afirst centering peg or pin 159 (FIG. 16) projects downwardly fromsurface 163. A second locating peg or pin 161 also projects downwardlyfrom this surface. When coupler 116 is in position on axle 30, pin orpeg 159 (FIG. 16) is inserted into centering hole 155 (FIG. 7). Inaddition, pin or peg 161 (FIG. 16) is positioned in hole 157 (FIG. 7).Desirably, the tolerances for the locations of holes 155,157 and pegs orpins 159,161 is very tight. For example, the center of centering hole155 and of pin 159 may be located within plus or minus 0.5 mm and thecenter of locating hole 157 and peg or pin 161 may be located withinplus or minus 0.1 mm. In addition, the diameters of the respective pins159,161 and holes 155,157 may be within plus or minus 0.25 mm. With thisconstruction, when coupler 116 is positioned on axle 30, the coupler isprecisely located. In addition, since in this embodiment therack-and-pinion steerer is mounted to the coupler 116, therack-and-pinion steerer is also therefore precisely positioned. Asimilar centering hole 155′ and locating hole 157′ (FIG. 7) cooperateswith a respective centering pin or peg 159′ (FIG. 13) and a respectivelocating pin or peg 161′ (FIG. 13) to precisely locate coupler 116′.

Again, axle couplers are not limited to these configurations and may beformed of plural pieces, although the illustrated construction isdesirable. In addition, the various components of the coupler may takeforms other than those shown in these figures while still performingfunctions such as mounting to an axle, supporting a rack-and-pinionsteerer, supporting an air spring and pivotally supporting a shockabsorber. In addition, the functions of the couplers may be performed bya single component or may be separated into plural spaced apart discretecomponents. For example, separate rack-and-pinion steering mounts may beused in addition to or instead of rack-and-pinion supporting portions ofthe couplers 116,116′. Furthermore, mirror images of these couplers maybe utilized, for example, if the lateral stabilizer orientation shown inFIGS. 1 and 2 is shifted end-for-end.

With reference to FIGS. 4 and 17 (and also visible in other figures),the axle assembly may also comprise a steering mechanism which desirablyis in combination with a suspension system such as disclosed herein. Adesirable form of steering mechanism comprises a rack-and-pinionsteering assembly 70. In the embodiment of FIG. 17, mounting brackets290,292 are utilized for coupling the rack-and-pinion steering assemblyto the solid axle 30 instead of utilizing portions 150,150′ of axlecouplers 116,116′ of FIGS. 1-6. The assembly 70 comprises adouble-acting rack-and-pinion steering mechanism 300 having respectivefirst and second end portions 302,304. A projecting rod portion 306 ofend portion 302 is pivoted at 308 to a rearwardly extending projection,such as to a knuckle portion 310, of wheel support 46. A projecting rodportion 312 extends outwardly from end portion 304. Rod portion 312 ispivoted at 314 to a rearwardly extending projection, such as to aknuckle portion 316, of the wheel support 48. These components are alsovisible in FIG. 4.

Desirably, the steering mechanism is shielded from the front by thesolid axle. More desirably, the rack-and-pinion mechanism issubstantially entirely shielded by the axle from the front. As can beseen in the embodiment of FIG. 5, the axle 30 is in front of therack-and-pinion steerer with only portions of the end portions 302,304of the rack-and-pinion (and in particular portions of the rod endportions) being visible when looking straight onto the axle from thefront of the vehicle. (See also FIG. 6).

Referring again to FIG. 17, the mounts 290,292 comprise respective baseportions 320,322 that are bolted, welded or otherwise fastened to axle30. These base portions are mounted in the FIG. 17 example to an uppersurface of axle 30. The bracket 290 comprises a rearwardly extendingrack-and-pinion steerer supporting portion 324 which, in this example,comprises a flange that overlays and supports the wheel steerer 70 fromabove. A rearwardly projecting portion 326 of bracket 292 similarlysupports the other end portion of steerer 70. Bolts or other fastenersmay be used to couple the wheel steerer 70 to the projecting portions324,326. The rack-and-pinion steerer 300 of assembly 70 may be like acommercially available rack-and-pinion mechanism, such as a Model LZS3,which has been modified by enlarging and strengthening the components(e.g., seals, ports, rack, and rods) for use in a truck axle mountedapplication. Model LZS3 rack-and-pinion mechanisms have been availablefrom Mercedes-Benz Corporation and are now available from ThyssenkruppPresta SteerTec GmBH.

In operation, as a steering wheel (not shown) is turned in a firstdirection, the rod end portions 306,312 shift together in one direction.This in turn, via the coupling knuckle portions 310,316, pivots therespective wheel supports 46,48 in a first direction to turn the wheelsof the vehicle in a direction opposite to the first direction. Turningthe steering wheel in the opposite direction reverses the direction ofmotion of the end sections 306,312 and steers the vehicle in theopposite direction. For example, if end portions 306,312 shift linearlyto the right in FIG. 17, the wheel supports 40,48 pivot in acounterclockwise direction about the steering axes 62,66 to steer thevehicle to the left in this figure. Conversely, turning the steeringwheel in the opposite direction shifts ends 306,312 in the oppositedirection (e.g., to the left) and pivots wheel supports 46,48 oppositely(e.g., clockwise) about the respective steering axes 62,66 to steer thevehicle wheels in the opposite direction. As the steering wheel isturned, hydraulic fluid is delivered from a pump to one port or theother of the rack-and-pinion wheel steerer 300 (e.g., see hydrauliclines 330,332 and ports 334,336 in FIG. 4) to provide a power assist tothe steering mechanism. The steering wheel is coupled to a steering stubshaft 340 (FIG. 17) which is connected to a bearing 342 carried by asupport 344. The support 344 may be mounted to the firewall of thevehicle. The stub shaft 340 is also coupled to a steering shaft 346which is coupled at its lower end to a valve actuator 348. As the shaft346 rotates, the valve actuator controls a valve to deliver hydraulicfluid to the appropriate side of a cylinder for a power steering assist.Desirably, the shaft 346 is a telescoping shaft with section 346Areceived within section 346B. The sections 346A, 346B are slidablerelative to one another to accommodate the motion of the suspension, butdo not rotate relative to one another. A commercially available I-shaft,such as #7025 474731 from ZFlenksysteme (ZFLS North America), is anexample of shaft 346. In addition, a rack within rack-and-pinionsteering mechanism 300 is shifted in the direction determined by thedirection of rotation of the steering wheel. Rubber boots 350,352protect the rack-and-pinion steerer against the influx of dust and thelike.

In one exemplary mechanism a universal joint couples the upper end ofshaft section 346B to a bearing 342. The bearing 342 is supported by abearing support carried by the firewall mounting assembly 344. The stubshaft 340 is coupled to bearing 342. In one embodiment, the firewallmounting assembly comprises a base portion, which may be of metal orother durable material, mounted to the firewall 349. An overstressrelieving member of the assembly 344 is mounted to the base and carriesthe bearing support. In the unlikely event that shaft sections 346A and346B seize up and prevent relative telescoping motion between the shaftsections to accommodate motion of the suspension, overstress relievingmember is designed to break so as to permit the bearing support andbearing to move relative to the firewall to accommodate the motion ofthe suspension without damaging the rack-and-pinion steering mechanism.As a result, vehicle steering is maintained as the steering wheelremains coupled to the rack-and-pinion steerer. The base may comprise amember that encircles the bearing 342 and stub shaft 340 such that baseprotects the firewall from damage by confining the motion of thesteering mechanism in the event the overstress relieving member breaksaway. Although the overstress relieving member may be made of anysuitable material that will break when a threshold of stress is reached,one specific example is nylon with a high glass content (e.g., nylon 6with 30 percent or more glass content) so that it is relatively brittleand tends to shatter when the break-away force is reached. An exemplarybreak-away force would be 700 pounds, although this can be varied. Theglass content of the nylon can be varied to adjust the break-away force.The overstress relieving member may, for example, be injected molded andmay alternatively be of plastic or other polymer materials. Amulti-piece construction for any of these components may be used. Inaddition, the break-away feature may be built directly into a firewallwithout, for example, the use of an assembly 344 or base member,although this would be less desirable. The exemplary break-away featureis exemplary and is not required.

The rack-and-pinion steerer of FIG. 17 may be used with any of thesuspensions described herein.

Desirably, the rack-and-pinion steerer 300 is mounted directly to theaxle 30 so that the steering mechanism moves up and down with the axle.One benefit of this construction is that the bump steering effectotherwise present in traditional pitman arm and drag link designs iseliminated. This construction also results in a reduction in the stresson the ends 306,312 of the rack-and-pinion steerer by reducing theextreme angular motion through which these components may otherwisetravel. This design also results in a significant weight savings overother steering mechanisms which utilize a Pitman arm, steering gear anddrag link.

FIGS. 18 and 19 illustrate other types of mounting brackets 380,382 toprovide additional examples of various mounting techniques which may beused to mount the steering mechanism 300 to the axle 30. In theembodiments of FIGS. 18 and 19, the axle 30 is provided with respectivespaced apart mounting shelves 384,386 which may be, for example, of agenerally planar flange-like configuration. A base 388 of the bracket380 is configured for mounting to the undersurface of shelf 384. Inaddition, a base 390 of the bracket 382 is configured for mounting tothe undersurface of shelf 386. Bolts or other fasteners may be used forthis purpose. As can be seen in FIG. 18, with this construction thebrackets do not overlie the upper surface of axle 30. Alternatively, thebrackets may overlie the axle. Centering holes or recesses 155,155′ andlocating holes or recesses 157,157′ such as discussed above inconnection with FIG. 7 may match corresponding centering holes andlocating holes or recesses in mounting brackets (for receivingfasteners) or locating pins or pegs in such brackets for use inprecisely mounting the mounting brackets in place. In addition,centering holes and mounting holes or pegs may be provided for the formof bracket shown in FIG. 18. The brackets 380,382 have respectiveupwardly extending riser portions 392,394 with rearwardly extendingflange portions 398,400 projecting from the upper end portions of theriser portions 392,394. The upper surfaces of flange portions 398,400may be flush with the upper surface of axle 30. The rack-and-pinionsteerer 300 may have mounting projections (e.g., 402,404 at one endportion thereof and 406,408 at the other end portions thereof) with theflanges 398,400 being connected, as by bolts (not shown) or otherfasteners to the rack-and-pinion steerer mounting projections.

In the embodiment of FIGS. 20-23, components which are similar to thoseshown in the FIGS. 1-6 embodiment are given identical numbers to thosein FIGS. 1-6 except with a double prime (″). In addition, in generalonly the suspension 90″ is numbered in these figures.

In the embodiment of FIGS. 20-23, elongated support 110″ is pivotallycoupled to frame rail 12 for pivoting about a single pivot axis 122″.The rear end portion 112″ of support 110″ is bent at its end to form acircular opening for receiving a bushing that is supported between innerand outer brackets of the illustrated coupling assembly 120″. A forwardportion of support 110″ is mounted to the axle 30″, such as byinterconnected upper and lower clamps, the lower clamp being shown as410 in FIG. 22. In the embodiment of these figures, the lower portion ofan air spring 130″ is secured to an extending portion 412 of theelongated support 110″ which projects forwardly of the axle. Aforwardmost end portion of support 110″ is indicated at 413 in FIG. 21.

As best seen in FIG. 22, in this embodiment a cross-member 80″, whichmay be of a C-shaped configuration with a central portion positionedlower than its end portions, has respective first and second endportions coupled to the respective frame rails 12,14 such as by bolts orother fasteners. The central portion of the cross-member 80 may, forexample, comprise an engine supporting cradle. In addition, in thisembodiment, although more than one lateral stabilizer may be used, anexemplary lateral stabilizer 240″ has a first end portion 242″ coupledto the end portion 413 of extension 412 of elongated support 110″. As aspecific example, stabilizer end portion 242″ is pivotally coupled to abracket 414 carried by the extension end 413. The bracket 414 includesspaced apart upwardly extending leg portions and a base portion. The endportion 242″ is pivotally supported between the upwardly extendingbracket legs and pivots about a pivot axis 416 (FIG. 21) which extendsdesirably in a fore-aft direction and parallel to the longitudinal axisof frame rail 12. The end portion 242″ of the stabilizer 240″ may beformed to define a circular opening for receiving a bushing with a pivotpin coupling the bushing to the bracket 414. The opposite end 244″ (FIG.22) of the illustrated stabilizer 240″ is pivoted to cross-member 80″ ata location intermediate to the ends of the cross-member. End 244″ isdesirably pivoted to the cross-member at a location which is nearer toframe rail member 14 than frame member 12.

In the embodiment of FIGS. 20-23, the cross-member 80″ and stabilizer240″ are positioned forwardly of the axle. More than one cross-memberand stabilizer may be used in the FIGS. 20-23 embodiment. In thisembodiment, one of the elongated supports is shorter than the other,although this is not required. That is, the longer elongated supportprovides a coupling location for the lateral stabilizer 240″. One formof radiator support and radiator (unnumbered) is also shown in the FIGS.20-23 embodiment.

Optional shock absorbers, such as shock absorber 170″ (FIG. 21) may beincluded in the suspension of FIGS. 20-23. For convenience, shockabsorber 170″ is only shown in FIG. 21, it being understood that asimilar shock absorber is desirably included in the suspension at theopposite frame rail 14. In this embodiment, shock absorber 170″ is shownpositioned rearwardly of the axle. At this location, the shock absorberprovides less of a dampening effect than when positioned forwardly ofthe axle as shown in the FIGS. 1-6 embodiment.

Another embodiment of a suspension and rack-and-pinion steeringmechanism is shown in FIGS. 24-31. Elements in common with those in theembodiment of FIG. 1 have been assigned the same numbers as in FIG. 1and will not be discussed further.

In the embodiment of these figures, the end portion 32 of axle 30 issuspended from frame rail 12 by a first leaf spring 430. In addition,the end portion 34 of axle 30 is suspended from axle 14 by a second leafspring 430′. Since the two suspensions are similar to one another, onlythe suspension including leaf spring 430 will be described in detail.Components included in the suspension with leaf spring 430′ have beenassigned the same numbers as those for the corresponding components ofthe suspension that includes leaf spring 430 except with a prime (′)designation. The leaf springs 430,430′ may include one or more leavesalthough the embodiment of FIG. 24 illustrates a leaf spring with asingle leaf.

Leaf spring 430 has a forward end portion 432 which is pivotally coupledto a bracket 434 for pivoting about an axis defined by a pin 436. Pin436 may support a bushing about which the end of leaf 430 is wrapped.Bracket 434 is coupled to the frame rail 12 at a location forwardly ofaxle 30.

The rear end portion 438 of leaf spring 430 is pivotally coupled toframe rail 12 at a location which is rearwardly of the axle andrearwardly of the rack-and-pinion steerer 70. In the embodiment of FIG.24, a mounting bracket 440 is coupled to frame rail 12. First and seconddownwardly projecting links 442,444 are pivotally coupled to bracket 440for pivoting about a pivot axis defined by a pin 446. The lower endportions of links 442,444 are pivotally coupled to leaf spring endportion 438 by a pin 448 for pivoting about a second pivot axis belowthe pivot axis defined by pin 446. Pin 448 may support a bushing withthe rear end of leaf spring 430 being wrapped around the bushing tocouple these components together.

The central portion 452 of leaf spring 430 is desirably coupled to theaxle end portion 32 and may be clamped to the axle. As best seen in FIG.26, a first mounting bracket 456 in this embodiment has upper and lowersurfaces with the lower surface overlaying an upper surface of a portionof axle end portion 32. A spacer 458, which may be of a Z-shapeconfiguration as shown in FIG. 26, although other shapes are suitable,is positioned on the upper surface of mounting bracket 456. Theundersurface of a central portion of leaf spring 430 overlies the spacer458. A top clamping member 460 engages the upper surface of leaf spring430 and more particularly a portion of the upper surface of the centralportion of the leaf spring.

Fasteners such as first and second U-shape clamping bolts 462,464 mayrest in respective upwardly opening grooves of clamping member 460. Itshould be noted in FIG. 24 that the clamping bolts 462,464 have beenomitted for clarity. One leg (the inboard leg) of fastener 462 passesthrough an opening 466 (FIG. 27) in mount 456 and through a legreceiving opening 468 (FIG. 26) in axle 30. The outboard leg of bolt 462passes through an opening 470 in the axle. In addition, the inboard legof bolt 464 passes through opening 472 in bracket 456 and through anopening 474 in the axle. The outboard leg of bolt 464 passes through anopening 476 in the axle. Nuts on the underside of the axle secure thebolts and the assembly in place. A locating hole 482 (FIG. 27) extendsthrough bracket 456 for receiving a fastener inserted through hole 482and a corresponding locating hole 484 in axle 30. A centering hole 486(FIG. 27) is also provided in base 456. Hole 486 is aligned with acentering hole or opening 488 in axle 30. In addition, centeringopenings 490,492 and 494 in the respective spacer 458, leaf spring 430and clamping member 460 are provided and are aligned with openings 486and 488 when the assembly is complete. A fastener, such as a bolt, maybe inserted through these centering openings and through the axle. Thecooperation of locating holes 482,484 and the centering holes486,488,490,492 and 494 when fastened by their associated fastenersprovide a tight tolerance for the mounting of bracket 456 to the axleand thus for mounting the rack-and-pinion steerer 70 via the bracket 456to the axle. That is, fasteners such as bolts inserted through openings496,498 in bracket 456 and through openings 500,502 of rack-and-pinionsteerer 70 mount the rack-and-pinion steerer to the base 456 and thus tothe axle. Desirably, the tolerance of the location of the center of thecentering holes including holes 486,488 is plus or minus 0.5 mm. Inaddition, desirably the tolerance of the location of the center oflocating hole 484 is plus or minus 0.1 mm. In addition, these holes havea diameter that is desirably within plus or minus 0.25 mm of theirspecified diameters. This same tolerance may also be provided forlocating hole 482′ and centering hole 486′ of bracket 456′ (FIG. 28) andfor the corresponding locating and centering holes 484′ and 488′ of theaxle.

The illustrated form of upper clamping member 494 includes an upwardlyprojecting stop portion 510 which may engage the undersurface of framerail 12 (FIG. 24) to limit the extent of downward deflection of the leafspring 430. In addition, clamping member 494 may include a shockabsorber mount portion 512. In the embodiment of FIG. 26, shock absorbermount 512 is positioned forwardly of the axis about which a wheelmounted to axle end portion 46 rotates.

As can be seen in FIG. 24, a shock absorber 514 may be positioned with alower end portion pivotally coupled to shock absorber mounting portion512. An upper end portion of the shock absorber may be pivotally coupledto a mounting bracket 516 which is coupled to the frame rail 12 and morespecifically mounted to the outboard side surface of the frame rail. Ascan be seen in FIG. 26, the shock absorber mount 512′ of clamping member464′ is shown at a position rearwardly of the axle 30. A lower endportion of a shock absorber 514′ is pivotally coupled to mountingportion 512′. The upper end portion of shock absorber 514′ is coupled bya bracket 516′ to the frame rail 14. Thus, with this construction, ascan be seen in FIG. 29, shock absorber 514 is positioned forwardly ofthe wheel axis while shock absorber 514′ is positioned rearwardly of thewheel axis. Alternatively, these shock absorbers may be mounted indifferent locations with, for example, both shock absorbers beingpositioned forwardly of the wheel axis.

As can be seen in FIGS. 30 and 31, in this construction as well as inthe earlier embodiments, desirably the wheel steerer 70 is shielded fromthe front by the axle except for the outermost end portions of the wheelsteerer such as portions of rod end 312, rod end 306, and a portion ofthe boot of end portion 302.

Having illustrated and described the principles of our invention withreference to several embodiments, it should be apparent to those ofordinary skill in the art that these embodiments may be modified inarrangement and detail without departing from the inventive principals.We claim as our invention all such modifications as fall within thescope and spirit of the following claims.

1-25. (canceled)
 26. A vehicle comprising a solid axle and first andsecond spaced apart elongated frame rail member members from which theaxle is suspended, the axle extending in a transverse direction relativeto the first and second frame rail members, at least one cross-memberinterconnecting the first and second frame rail members at a locationforwardly of the axle, a suspension for the axle of the vehiclecomprising: a first elongated support comprising a first end portionpivotally coupled to the first frame rail member at a locationrearwardly of the axle and comprising a second end portion extendingforwardly of the axle, the first elongated support also being coupled tothe axle; a first air spring coupled to the first frame rail member andto the first elongated support, the first air spring having a centerwhich is positioned at a location forwardly of the axle; a stabilizermember coupling the second end portion of the first elongated support tothe cross-member; a second elongated support comprising a first endportion pivotally coupled to the second frame rail member at a locationrearwardly of the axle and comprising a second end portion extendingforwardly of the axle, the second elongated support being coupled to theaxle; and a second air spring coupled to the second frame rail memberand to the second elongated support, the second air spring having acenter which is positioned at a location forwardly of the axle.
 27. Anapparatus according to claim 26 wherein the first elongated supportextends forwardly to a greater extent than the second elongated support.28. An apparatus according to claim 26 wherein the first and secondelongated supports are each of a unitary one-piece monolithicconstruction.
 29. An apparatus according to claim 26 wherein the firstend portion of the first elongated support is pivotally coupled to thefirst frame rail member so as to pivot relative to the first frame railmember about only a first pivot axis, and wherein the first end portionof the second elongated support is pivotally coupled to the second framerail member so as to pivot relative to the second frame rail memberabout only a second pivot axis.
 30. An apparatus according to claim 29comprising a first bracket rigidly mounted to the first frame railmember and projecting downwardly from the first frame rail member, thefirst bracket having a first bracket distal end portion spaced from thefirst frame rail member, the first elongated support being pivoted tothe first bracket distal end portion so as to pivot about the firstpivot axis relative to the first bracket and thereby relative to thefirst frame rail member, the suspension further comprising a secondbracket rigidly mounted to the second frame rail member and projectingdownwardly from the second frame rail member, the second bracket havinga second bracket distal end portion spaced from the second frame railmember, the second elongated support being pivoted to the second bracketdistal end portion so as to pivot about the second pivot axis relativeto the second bracket and thereby relative to the second frame railmember.
 31. An apparatus according to claim 26 in which the vehiclecomprises first and second wheels rotatably coupled to respective endportions of the axle for rotation as the vehicle moves, the first andsecond wheels also being pivotally coupled to the respective endportions of axle for pivoting relative to the axle about respectiveupright steering axes to steer the vehicle, the apparatus furthercomprising a rack-and-pinion wheel steerer mounted to the axle andcomprising first and second rack-and-pinion end portions respectivelycoupled to the respective first and second wheels, the rack-and-pinionsteerer being operable to selectively shift the first and secondrack-and-pinion end portions in a first direction to pivot the wheelsabout the respective steering axes in one direction, and therack-and-pinion steerer being operable to selectively shift the firstand second rack-and-pinion end portions in a direction opposite to thefirst direction to pivot the wheels about the respective steering axesin a second direction opposite to said one direction.
 32. A vehiclecomprising a solid axle extending at least between first and secondframe rail members, first and second wheels rotatably coupled torespective end portions of the axle for rotation as the vehicle moves,the first and second wheels also being pivotally coupled to therespective end portions of the axle for pivoting about respectiveupright steering axes and relative to the axle to steer the vehicle, arack-and-pinion wheel steerer mounted to the axle and comprising firstand second rack-and-pinion end portions respectively coupled to therespective first and second wheels, the rack-and-pinion wheel steererbeing operable to selectively shift the first and second rack-and-pinionend portions in a first direction to pivot the wheels in one directionabout respective upright steering axes, and the rack-and-pinion steereralso being operable to selectively shift the first and secondrack-and-pinion end portions in a second direction opposite to the firstdirection to pivot the wheels about respective upright steering axes ina direction opposite to said one direction.
 33. An apparatus accordingto claim 32 in which the rack-and-pinion steerer is supported and sizedso as to be positioned behind the axle and is substantially shieldedfrom the front by the axle.
 34. An apparatus according to claim 33 inwhich only a portion of the first and second end portions is notshielded from the front by the axle.
 35. An apparatus according to claim32 comprising first and second suspensions each comprising a leaf springfor suspending the axle from the first and second frame rail members.36. An apparatus according to claim 32 comprising first and secondsuspensions each comprising an air spring for suspending the axle fromthe first and second frame rail members.
 37. An apparatus according toclaim 32 further comprising; first and second spaced apartrack-and-pinion mounts, each rack-and-pinion mount comprising a baseportion for mounting to the axle and a projecting portion extendingrearwardly from the axle, the rack-and-pinion steerer being supported bythe projecting portions of the first and second rack-and-pinion mounts.38. An apparatus according to claim 37 wherein each of therack-and-pinion mounts comprises a shock absorber supporting portionprojecting forwardly of the axle, the apparatus further comprising afirst shock absorber having a first shock absorber end portion coupledto the first frame rail member and a second shock absorber end portioncoupled to the shock absorber supporting portion of the firstrack-and-pinion mount, and a second shock absorber having a first shockabsorber end portion coupled to the second frame rail member and asecond shock absorber end portion coupled to the shock absorbersupporting portion of the second rack-and-pinion mount.
 39. An apparatusaccording to claim 37 wherein each mount further comprises a couplerwith an air spring supporting portion. 40-44. (canceled)